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Olympia, WA, United States

Waters C.D.,University of Washington | Hard J.J.,National Oceanic and Atmospheric Administration | Brieuc M.S.O.,University of Washington | Fast D.E.,Yakama Nation Fisheries | And 4 more authors.
Evolutionary Applications

Captive breeding has the potential to rebuild depressed populations. However, associated genetic changes may decrease restoration success and negatively affect the adaptive potential of the entire population. Thus, approaches that minimize genetic risks should be tested in a comparative framework over multiple generations. Genetic diversity in two captive-reared lines of a species of conservation interest, Chinook salmon (Oncorhynchus tshawytscha), was surveyed across three generations using genome-wide approaches. Genetic divergence from the source population was minimal in an integrated line, which implemented managed gene flow by using only naturally-born adults as captive broodstock, but significant in a segregated line, which bred only captive-origin individuals. Estimates of effective number of breeders revealed that the rapid divergence observed in the latter was largely attributable to genetic drift. Three independent tests for signatures of adaptive divergence also identified temporal change within the segregated line, possibly indicating domestication selection. The results empirically demonstrate that using managed gene flow for propagating a captive-reared population reduces genetic divergence over the short term compared to one that relies solely on captive-origin parents. These findings complement existing studies of captive breeding, which typically focus on a single management strategy and examine the fitness of one or two generations. © 2015 John Wiley & Sons Ltd. Source

Knudsen C.M.,Oncorh Consulting | Pearsons T.N.,Grant County Public Utility District | Beall E.P.,French National Institute for Agricultural Research | Fast D.E.,Yakama Nation
Environmental Biology of Fishes

In 1997 the Cle Elum Supplementation Research Facility was established to enhance spring Chinook salmon returning to the upper Yakima River, Washington State. This effort increased spring Chinook abundance, yet conditions at the hatchery also significantly elevated the occurrence of jacks and yearling precocious males. The potential genetic effect that a large influx of early maturing males might have on the upper Yakima River spring Chinook population was examined in an artificial stream. Seven independent groups of fish were placed into the stream from 2001 through 2005. Males with four different life history strategies, large anadromous, jacks, yearling precocious, and sub-yearling precocious were used. Their breeding success or ability to produce offspring was estimated by performing DNA-based pedigree assessments. Large anadromous males spawned with the most females and produced the greatest number of offspring per mate. Jacks and yearling precocious males spawned with more females than sub-yearling precocious males. However, jacks, yearling and sub-yearling precocious males obtained similar numbers of fry per mate. In the test groups, large anadromous males produced 89%, jacks 3%, yearling precocious 7%, and sub-yearling precocious 1% of the fry. These percentages remained stable even though the proportion of large anadromous males in the test groups ranged from 48% to 88% and tertiary sex ratios varied from 1. 4 to 2. 4 males per female. Our data suggest that large anadromous males generate most of the fry in natural settings when half or more of the males present on a spawning ground use this life history strategy. © 2011 The Author(s). Source

Larsen D.A.,National Oceanic and Atmospheric Administration | Harstad D.L.,National Oceanic and Atmospheric Administration | Strom C.R.,Cle Elum Supplementation and Research Facility | Johnston M.V.,Nelson Springs Research Center | And 3 more authors.
Transactions of the American Fisheries Society

In male Chinook Salmon Oncorhynchus tshawytscha, age of maturation is phenotypically plastic, occurring at age 1 (referred to as precocious parr or microjack), age 2 (minijack), age 3 (jack), age 4, or age 5. Microjacks and minijacks are thought to forego migration to the ocean as smolts, instead remaining in headwaters and employing a "sneaking" strategy to fertilize eggs. We compared the prevalence of minijacks (minijack rate) among hatchery- and natural-origin spring Chinook Salmon from the Yakima River, Washington, over seven brood years (2001-2007). We quantified minijack rates and sex ratios in the hatchery population prior to release and during out-migration at a trap located 230 km downstream. Within this time period, we also monitored minijack rates in a 3-year (brood years 2002-2004) growth study designed to reduce minijack production at the hatchery. Minijacks made up an average of 41% of the male population in the hatchery, but annual minijack rates varied in response to the growth rate or fish size at release. Average minijack rate was approximately 20% among out-migrating hatchery fish, about half the rate found prior to release. Among out-migrants, minijack rates of hatchery fish were approximately 10 times those of natural-origin fish, but sex ratios were significantly skewed toward females in both hatchery- and natural-origin groups. Data from this study and related studies suggest that the predominant age of early male maturation in the Yakima River and similar rivers is age 2 (minijack) in hatchery fish and age 1 (microjack) in natural-origin fish. Based on this and other studies, we now recognize three minijack life history types in spring Chinook Salmon: resident, fluvial, and anadromous, depending on the migration pattern exhibited in the spring and summer. Finally, we discuss the broader impacts that high minijack production may have on the establishment of size-at-release targets for salmon supplementation programs in the future.Received July 11, 2012; accepted November 13, 2012. © 2013 Copyright Taylor and Francis Group, LLC. Source

Knudsen C.M.,Oncorh Consulting | Beall E.P.,French National Institute for Agricultural Research | Fast D.E.,Yakama Nation
Transactions of the American Fisheries Society

Spring Chinook salmon Oncorhynchus tshawytscha native to the upper Yakima River, Washington, were placed into an artificial stream to evaluate the effect of a single generation of hatchery culture on their spawning behavior and ability to produce offspring. From 2001 to 2005, seven independent test groups containing wild and hatchery fish were placed into the stream. The effects of body weight, spawning ground longevity, attack frequency, social dominance, courting frequency, and mate number on breeding success in hatchery and wild males were evaluated. Male breeding success increased with body weight, while spawning ground longevity was negatively associated with breeding success. Although important, body weight had a lesser effect on male breeding success than did social dominance or attack frequency. Males with high attack and courting frequencies produced the most progeny; of the traits examined, the number of female spawning partners explained the greatest amount of variation (average r2 = 80%) in male breeding success. Differences in male agonism due to male origin were found. Wild males exhibited higher attack rates and greater social dominance than did hatchery males. However, the observed inequalities in agonism and dominance appeared to be largely caused by differences in body weight between the two types of males: Wild males were, on average, 9% heavier than hatchery males. Wild and hatchery males did not differ in the frequency of courting behaviors or in the number of mates. Pedigree analyses based on DNA showed that hatchery and wild males had comparable breeding success values. Consequently, a single generation of hatchery exposure appeared to have a low effect on spring Chinook salmon male breeding success in our experimental setting. © Copyright by the American Fisheries Society 2010. Source

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